This application concerns automobile engines and particularly an automobile engine including an air and fuel heater which is energized through an engine start anticipator prior to any attempts to start the engine.
It is known to utilize electrical heaters for vaporizing fuel and for heating air and fuel entering an engine. This has been previously contemplated to promote engine starting, particularly in cold weather. Previous heaters have utilized resistance wire grids. Another known type of heater utilizes ceramic material which is molded or extruded into a grid configuration. An example of this type of heater is found in U.S. Pat. No. 3,846,723 and is assigned to Texas Instruments. This type of heating element is desirable in that the resistance is low at low temperatures but as the grid increases in temperature, the resistance also increases thereby limiting the maximum electrical current utilized after the grid reaches an operating temperature. A problem with electrically energized heating grids for heating fuel and air is the delay between energization of the heating grid and achieving a satisfactory and workable temperature thereof so that fuel is evaporated. When a heating grid is energized and an engine is immediately cranked in cold weather, an appreciable period of time extends before the heating grid becomes effective to aid in engine starting.
It has been found that a vehicle engine equipped with an early fuel evaporator as described heretofore will substantially decrease the period of time necessary for the starter motor to operate. This of course extends its durability and imposes less strain on the battery and other electrical components. The conventional manner of energizing the early fuel evaporator is by a circuit controlled by the vehicle ignition switch. This type of control system does decrease starter operating to some extent but is wasteful because the early fuel evaporator needs a short period of time in which to reach operating temperatures. When the ignition switch is first switched on the early fuel evaporator is energized but almost immediately thereafter the engine starter motor is also energized during a normal start-up. It is desirable to provide a system which energized the early fuel evaporator unit a short period of time prior to operating the vehicle starter motor. To this end the subject early fuel vaporizer system has been developed. A pre-ignition anticipator controls the heater. One desirable pre-ignition anticipator utilizes switch means activated by opening of the driver's door as he or she enters the vehicle. It is also possible to utilize switch means operated by the door opening handle mechanism. Another anticipator might take the form of switch means which is activated by the driver's weight on the seat cushion. The purpose of utilizing any of the aforementioned anticipators is to activate the fuel vaporizer heating unit a short period of time before actual operation of the vehicle starter.
Therefore, an object of the present invention is to provide a fuel-air heating system for a vehicle and activated prior to start cranking to permit desirable high temperatures to be attained.
A further object of the present invention is to provide a vehicle fuel-air heating system utilizing an electrically heated grid located downstream from fuel introduction means such as a carburetor which initiates the heat cycle a short period of time prior to actual operation of the vehicle starter motor so that the heater will attain a proper operating temperature prior to attempted engine starts.
Further objects and advantages of the present invention will be more readily apparent from a reading of the following detailed description of preferred embodiments, reference being had to the accompanying drawings in which embodiments are illustrated.